1. Field of the Invention
This invention is generally directed to masonry building blocks and more specifically to hollow core concrete blocks which are designed to function as inspection blocks by having incorporated therewith premolded openings by way of which an inspection may be made of the interior of a core from the face of the blocks. The openings in the blocks of the present invention are designed to function to retain transparent inspection windows or plates which are mounted within the blocks and are seated against flanges created or defined by the side edges of the openings. The openings in the block are also designed so that the blocks may be placed either top side up or top side down in the construction of a wall.
2. History of the Related Art
In many localities it is necessary to reinforce masonry construction such as walls formed of concrete hollow core building blocks by incorporating therewith steel dowel rods which are connected through the hollow cores of the blocks to steel dowel rods extending from the building foundation in such a manner that the walls are united to the steel extending therethrough. Conventionally, in residential concrete block construction steel dowel rods must be provided at specified intervals such as every sixteen feet and at each corner of a structure. In commercial construction the distance between the steel reinforcing often is decreased and therefore reinforcing distances of eight feet or less in some localities is standard.
In order for building inspectors or engineers to ensure that concrete block walls have been properly reinforced and that proper connections are made between the steel reinforcing rods extending therethrough, it is necessary to provide an "inspection hole" in the concrete blocks which are laid adjacent the foundation. Failure to provide the proper placement, overlapping and tying of the steel within the concrete walls can lead to wall failure, especially in those localities wherein environmental conditions are conducive to high winds generated by hurricanes, tornadoes or earthquakes. By way of background, the steel dowel or reinforcing rods which are embedded and which extend vertically from the foundation are tied to steel dowel rods which extend upwardly through aligned cores or hollow cells of the building blocks so that each course of blocks is tied to the remaining courses throughout the height of the wall. Along the top course, horizontally oriented steel rods are tied to the vertical rods thereby connecting the overall wall structure both horizontally and vertically. To further stabilize the steel within the concrete blocks and to ensure that the steel is locked to the blocks, each vertically open column defined by the aligned cells or cores of the blocks through which such steel extends are filled with concrete, mortar or other cementitious material after the proper placement of the steel has been assured by a building inspector or engineer. Unfortunately, to enable a vertical open column to be filled with a concrete or mortar material it is necessary to close the opening which forms the "inspection hole" in the blocks which are adjacent to the foundation.
In order to close the openings in conventional concrete blocks it is generally necessary to place a board against the face of the block and across the opening therein which forms the "inspection hole" and thereafter bracing the board to ensure that it remains against the face of the block as the cementitious material is poured within the hollow column. Frequently however, due to the weight of the material within the hollow column, the boards which are placed across the openings will fail allowing concrete to emerge through the "inspection hole" opening. Such accidents create a great deal of work to not only clear the area of the spill but to thereafter reinforce the opening and again fill the column with concrete.
Conventional "inspection holes" are formed generally in two manners. Generally, a worker on the job site either uses a hammer to chip and remove a portion of the facing of a hollow core concrete block to establish an opening therein or a power saw is used to cut the opening in the face of the concrete block. The openings permit workers to tie the steel within the blocks and also allow inspectors to determine whether proper joints have been created between the steel extending from the foundation and the steel within a wall.
Conventional methods of forming inspection holes are not only time consuming and man power inefficient but such techniques are often hazardous to workers. Utilizing a saw to cut openings in concrete blocks results in the creation of dust which not only presents a problem for inhalation but also a problem with regard to safety and protection of worker's eyes. Further, utilizing either conventional technique, blocks are frequently cracked or shattered during the cutting or chipping process and therefore materials are wasted.
In order to overcome some of the foregoing problems, some block companies have proposed to provide precut openings in blocks. Such openings are generally U-shaped in configuration and thus do not recognize the need to provide a block with an inspection hole opening which may be utilized when laid upside down. It is often necessary for block masons to lay the U-shaped precut block upside down due to the running bond and/or specifications from the general contractor that all inspection hole openings be placed on the inside or outside of a particular wall or building. Therefore, the remaining part of the U-shaped opening has to be removed by saw cutting or chipping so that all block and mortar debris can be removed flush with the concrete floor prior to inspections. Further, simply providing precut openings in the face of hollow core concrete blocks does not provide a solution to the need to seal the openings in the concrete blocks when it becomes necessary to fill a vertical column of hollow cores through which steel dowel rods have been placed with concrete or mortar. Some prior art building block structures which have openings created in their sides are disclosed in United States design patent U.S. Pat. No. 266,363 to Santos, and United States utility patents U.S. Pat. No. 1,065,762 to Ainsworth et al., U.S. Pat. No. 1,302,667 to Jones, U.S. Pat. No. 3,015,408 to Campbell et al., U.S. Pat. No. 3,123,244 to Amundson and U.S. Pat. No. 3,674,913 to Yates.